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/* -*- coding: utf-8 -*- */
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* Passprompt - Read a password from a FIFO and output it
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* Copyright © 2008 Teddy Hogeborn
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* Copyright © 2008 Björn Påhlsson
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* This program is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see
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* <http://www.gnu.org/licenses/>.
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* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
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* <https://www.fukt.bsnet.se/~teddy/>.
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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY() */
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#include <sys/types.h> /* ssize_t */
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#include <sys/stat.h> /* mkfifo(), S_IRUSR, S_IWUSR */
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#include <iso646.h> /* and */
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#include <errno.h> /* errno, EEXIST */
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#include <stdio.h> /* perror() */
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#include <stdlib.h> /* EXIT_FAILURE, NULL, size_t, free(),
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realloc(), EXIT_SUCCESS */
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#include <fcntl.h> /* open(), O_RDONLY */
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#include <unistd.h> /* read(), close(), write(),
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int main(__attribute__((unused))int argc,
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__attribute__((unused))char **argv){
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const char passfifo[] = "/lib/cryptsetup/passfifo";
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ret = TEMP_FAILURE_RETRY(mkfifo(passfifo, S_IRUSR | S_IWUSR));
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if(ret == -1 and errno != EEXIST){
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int fifo_fd = TEMP_FAILURE_RETRY(open(passfifo, O_RDONLY));
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size_t buf_allocated = 0;
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const size_t blocksize = 1024;
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if(buf_len + blocksize > buf_allocated){
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char *tmp = realloc(buf, buf_allocated + blocksize);
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buf_allocated += blocksize;
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sret = TEMP_FAILURE_RETRY(read(fifo_fd, buf + buf_len,
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buf_allocated - buf_len));
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buf_len += (size_t)sret;
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TEMP_FAILURE_RETRY(close(fifo_fd));
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/* Print password to stdout */
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while(written < buf_len){
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sret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO, buf + written,
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written += (size_t)sret;